Introduction to Computing

 

As one member of the faculty at Juniata College once said “a computer doesn't even make a good boat anchor without software”!  How true this is.  In fact though, an operating system is also useless if it doesn’t have hardware and furthermore, who would really want a PC if it all it had was hardware and an operating system?  Well a few folks would still want one, but the majority of us need software (WORD, EXCEL, email, instant messaging, games, etc…).  The hardware, the software, and the operating system (a form of software) must all come together each time we use our computers.  In short, we gain access to the hardware through the software and the operating system allows us to do this.

In this section, we will discuss the basic hardware components of your typical PC and then venture into software and operating systems.  In truth, we could spend weeks and weeks (even years) learning about the technologies in a computer.  We will spend only a few weeks on this topic, with the main goal being to introduce you to and familiarize you with the workings of a computer.  We will begin with hardware components and then explore software (both operating systems and applications). 

Overview of Computer Hardware

While it may seem that computer hardware has changed dramatically over the past few decades, in reality, the basics remain the same.  There are still four primary types of computer hardware: input devices, processing components, secondary storage, and output devices. 

We’ll address the main function of each of these components and then we’ll review how each of these devices has changed over the years and what to expect in the future.  In other words, we’ll begin to address “state of the art” computer components and how they provide an advantage over yesterday’s hardware.  Perhaps we will uncover disadvantages as well!  Before going on, it should be noted that there is a wealth of information available on the internet regarding computer hardware components.  A few nice overviews can be found as follows:

http://distance-ed.fullerton.edu/pages/students/tutorials/hardware1.htm

http://is.polytechnic.edu.na/material/Hardware/HWOverv.htm

http://claymore.engineer.gvsu.edu/eod/hardware/hardware-3.html

http://starrlab.tamu.edu/STARRLAB/Courses/01Fall/RENR201/Handouts/HardwareSoftware/Index.htm

 

Primary Hardware Components:

Input Devices:

If you are gong to work with your computer, you have to have some way of providing input.  Input devices include various devices that enable the computer to receive information (either data or computer programs) so that it may be processed.  Traditional input devices include a keyboard, mouse, and external data storage (referred to as secondary storage and will be covered in a separate section since it is also an output device).  Document scanners, automatic teller machines (ATM's), point-of-sale devices, touch sensitive screens, bar code readers, various other optical scanners such as retinal scanners (used for identification purposes), finger print scanners, digital cameras, video recorders, and voice recorders are becoming more popular as input devices.  Many predict that keyboard entry will become obsolete in the near future.  Improvements in voice recognition software and decreased prices of such software will help make this a reality.  The input devices are what enable you to interact with the computer.  Thus we often talk about human-computer interaction (HCI).  The study of HCI is a rapidly growing field.  While there are many sites and interesting resources for this field, here are a few:

http://www.hcibib.org/

http://www.hcirn.com/

http://www.ida.liu.se/labs/aslab/groups/um/hci/

Processing Components:

Computer processing components generally include the control unit, arithmetic/logic unit, register storage area, and memory (primary storage).  The control unit and arithmetic/logic unit together are referred to as the central processing unit (CPU).  When distinguishing between different types of computers, people typically talk about the CPU, also referred to as the processing chip.  Intel developed and introduced the first microprocessor in 1971.  It was a very slow chip (compared to today’s chip speeds).  Not only was it slow – but it could only add and subtract!  Later, Intel marketed an entire series of chips that includes the Pentium chips that are prevalent in today’s computers.  Before the microprocessor, engineers had to “string together” single chips or transistors to perform a series of tasks (like adding 2 numbers together).  Transistors are small pieces of silicon (3 layers) that form a sort of tiny little sandwich that current can pass through.  If current is passing through a transistor then we say 1 “bit” has passed through.  If no current passes then this is a 0 bit.  You will read more about the familiar bits and bytes shortly.  The use of silicon should give you a hint as to the nickname “Silicon Valley”.    Even in the 1970’s on very early Intel chips, such as the 8080, there were 6,000 transistors.  In comparison, today’s Pentium 4 chip as 42,000,000 transistors and is literally thousands of times faster!  Howstuffworks has a very nice section on microprocessors and links to Intel’s pressroom on the history of microprocessors: http://computer.howstuffworks.com/microprocessor.htm 

There is an interesting thought known as Moore’s law.  This essentially says that if research stays constant and competition also remains constant, then processor speeds will double every 18 months.  Intel has some information on this: http://www.intel.com/research/silicon/mooreslaw.htm .  It is especially interesting given that this thought or observation was made in 1965!  Webopedia also provides some discussion: http://www.webopedia.com/TERM/M/Moores_Law.html

To sum it up, the CPU is where is all happens.  It is the brain – so to speak – of your computer.  The CPU takes instructions (usually from a software package talking to it through an input device) and acts on these instructions, creating output.  When the CPU gets instructions (this is really data to a CPU) it puts them into RAM or random-access memory.  This is sometimes called the main or primary memory.  It wasn’t all that long ago that 32 or 64 Mb of RAM was plenty.  Now most computers have a minimum of 256Mb of RAM.  Why?  Because today’s software packages have a lot of instructions for the CPU.  While the CPU is working, the RAM is holding data and instructions, and even the results until these results are saved to a storage device (hard disk, CD, etc..).  One noteworthy item about RAM is that for RAM to hold or store data (input, output, instructions, etc…) electricity or current must be present.  We say that memory is "volatile". This means that when you turn of the computer – everything in RAM is gone!  Ever had this happen to you?  Have you ever had your roommate accidentally (on purpose) turn off your computer?  You lose all work!  Many software packages (e.g. MS WORD) have auto backup features.  These programs keep track of changes of unsaved work.  If the power goes off, then you may see a “recovered” version of the document the next time you open WORD (as an example).  However, these backup features are not constant, so you may not have retrieved all of your lost work.

Read-only Memory

Read-only memory or ROM is similar to RAM in that the device holds data; however, the ROM is a special kind of memory in that it is permanent (read-only).  We call this memory "nonvolatile". You cannot erase the data (instructions, etc.).

The Cache (pronounced "cash" as in $)

Cache is another type of memory that you may have heard of before.  The cache is another special kind of memory that the CPU uses.  If you go to dictionary.com and enter the word “cache”, you will get:

1.  
1. A hiding place used especially for storing provisions.
2. A place for concealment and safekeeping, as of valuables.
3. A store of goods or valuables concealed in a hiding place: maintained a cache of food in case of emergencies.
2. Computer Science. A fast storage buffer in the central processing unit of a computer. Also called cache memory.

In the computer world, this is really no different.  It is a hiding or storing place.  It is a place in memory that “common tasks” are stored, so that the computer doesn’t have to go get these tasks or this data continuously.  You see, your CPU is quite fast; however, retrieving data or instructions from a hard drive (or secondary storage device) is not nearly as fast.  So we can cache some items and help to speed things up!  Webopedia also offers a nice discussion on the cache: http://www.webopedia.com/TERM/c/cache.html.

BITS AND BYTES

Many of you may be aware of the concept of bits and bytes; however it is still worth noting this again.  While we see output in the form of words, images, and other forms, the computer generally communicates between various components using a digital language – binary.  Binary is the mode of transferring data (input, output, programs, etc..).  The binary data are in the form of bits, which is either a 0 or 1 – hence the term binary.  You may even hear someone use the term binary in another context, meaning that there are only two choices.  The term bytes comes from a series of bits.  Eight (8) bits equals a byte (usually).  We often refer to the speed or capacity of a CPU in terms of the bit capacity.  Thus an 8-bit processor is slower than a 16-bit and so on.  The recently introduced Macintosh G5 is a 64-bit processor!

You may have heard someone say that they have a 100 Gigabyte hard drive. What does this really mean? How big is 100 Gigabytes? Here's a simple conversion table:

1 bit = 0 or 1

8 bits = 1 byte

1024 bytes = 1 Kilobyte (1 K)

1024 Kilobytes = 1 Megabyte (1 M or a "meg")

1024 Megabytes = 1 Gigabyte (1 G or a "gig")

1024 Gigabytes = 1 Terabyte (1 T)

So 100 Gigabytes is 102400 Megabytes, which is 104857600 Kilobytes, which is 107374182400 Bytes, or 858993459200 bits (1's and 0's).

The Motherboard

The motherboard houses the computer processing components as well as other essential components such as capacitors, jumpers, anti-static foam, and input/output connections like serial and parallel ports, USB ports, keyboard connector, and bus slots.  Take a look at the typical components in a motherboard:

Source: http://starrlab.tamu.edu/STARRLAB/Courses/01Fall/RENR201/Handouts/HardwareSoftware/MotherBoard.htm

 

Computers and computer equipment and devices are evolving rapidly.  As such, prices are constantly dropping.  Consider web cameras, once a sort of technological luxury, they have now lost their novelty and can even be purchased for under $10.00. In addition to cost dropping, the size of hardware devices is also shrinking.  While many applaud the advantages of low cost micro-sized devices, there are also down sides to these advances.  Privacy may no longer be a luxury we can take for granted.  Many of you may have already been an unwilling actor on someone’s web cam.

 

Moodle Discussion Assignment:  Decreases in the cost of computer components leads to increases in availability and consequently, the rapid diffusion of new technologies.  Think about a new computer technology that you believe will flood the market in the near future.  Why do you think people will want this product?  What are the advantages and disadvantages of having this product?  Please go to Moodle and navigate to the appropriate discussion activity. 

 

Ports

One of the last things we should discuss in terms of hardware are “ports”.  Ports exist on your computer in several forms and allow you to add on a number of additional hardware devices.  A port connects directly to your motherboard and thus interfaces or talks to other elements of your computer.  We are going to discuss a number of the more common ports or connections for peripheral items:  parallel, serial, USB, firewire.

Serial – Serial ports have been around for quite a while (at least in terms of computer technology).  They are called serial ports because they transmit data in a line – so to speak.  Thus the bytes are torn apart and the bits transfer in a line – one at a time.  You need only one wire for this – but it is fairly slow – again compared to other forms.  Your phone modem probably comes through a serial port.  Most computers currently have 2 serial ports – they are the little opening with 9 pins or pin holes and are often called COM ports.

Parallel – Parallel ports are much larger in size and typically have 25 pins or pin holes.  Printers are most commonly connected to parallel ports.  As the name implies, data is transmitted in parallel and the connections tend to be much faster than serial ports.

USB – USB ports or Universal Serial Bus ports are fairly new.  These are not only very fast (transmitting a lot of data) but they are very flexible.  Only a few years ago, most computers came with 1 parallel port and 2 serial (COM) ports.  Connecting a number of devices was tedious and annoying.  Some peripherals have “pass through” ports – meaning a device connects to your parallel port and also has a parallel port on the back side to reconnect your printer or other device.  USB’s allow you to connect over100 devices to your computer.  Most modern operating systems automatically detect “new hardware” when you plug it in to a USB port.  This is called “plug and play” hardware.  You can easily and inexpensively add on a USB hub, which is nothing more than a plug that goes into your USB port and then has several more USB ports available.  It is kind of like a power strip that allows you to plug in several appliances at once.  The USB port is the small rectangular port on the back of your computer.  It is about 1.2 inch long and 3/16 inch high.  Because of the popularity of USB ports (almost all peripherals now come with USB connections), a lot of computers now have USB ports in the front for ease of use.  USB 1.0 was the most common USB connection and this runs at about 12Mbs.  Currently, USB 2.0 has been introduced and it runs at over 400 Mbs!

Firewire – This is another type of connection that is similar in nature (physically) to USB connections.  Firewire is also very fast at around 400 Mbs.  It connects to your computer through a firewire port that is similar to a USB port.  USB and Firewire ports are not interchangeable.  USB 2.0 and Firewire are very similar in speed. 

SCSI – The SCSI or Small Computer Systems Interface is pronounced “scuzzy”.  This connection is really more a component to your PC.  It is often internal and it is what many devices like CD-ROM’s use.  They are fast at around 160 Mbs.

Video – The video port is what video devices like your monitor or projector use to receive output.  Today, many computers come with a digital video output.

 

 

Secondary Storage:

There are many types of secondary storage devices.  One of the earliest types of secondary storage was the “punch card” system.  These systems literally used cards with holes punched out to store or remember data.  Early programmers used these punch cards and fed a stack of these cards into a card reader that converted the stored data into a digital (bits and bytes) format.  You would often see programmers walking around with stacks or decks of punch cards.  One nice thing was that they also served as a place to write notes and they made good coasters.

http://www.fourmilab.ch/documents/univac/cards.html

Modern storage devices include magnetic tapes, memory cards, and disks (from floppy disks to hard drives), digital video disks (DVD's) and CD-ROMS, CD-W (CD-writable), and CD-RW (CD rewritable).  New external storage devices also provide easy, portability storage. For example, the memory stick, or thumb drive, enables the user to carry data around (usually a 64 MB to 264 MB capacity) on a small device that can be attached to a key chain.  The memory stick looks like a stick but is the size of a thumb. 

Below is a list of common (and not so common storage devices).  How many have you used or seen?

• 5 ¼ inch floppy
• 3 ½ inch floppy
• Zip Drive (100 and 250)
• CD
• DVD
• Optical
• Memory Stick
• USB Hard Drives
• Magnetic Tapes

Can you name any others?

 

Output Devices:        

As we have discussed, output comes from the CPU after having “crunched” the data that the CPU got from some input device.  As we will soon discuss, the CPU knows how to crunch this data by following the software instructions.  Monitors, printers, and plotters (and storage, as discussed above) are standard output devices.   However, advances made to each of these devices are anything but standard.  Flat screen and touch screen monitors are some recent advances in everyday monitors.  But, look into the medical field and advances in monitors take on a whole new look, anywhere from new diagnostic equipment to real-time surgery advances. 

Beyond the laser jet and ink jet worlds, printers are out there producing anything from bar codes to bill boards.  And, thanks to digital cameras, the novice photographer can edit and print his/her own photography.  Are we increasing productivity or simply adding functions which divert our attention from our real goals?  As with any new technology, it is up to the user how and why we use these new technologies!   

 

Common Computer Types

The last thing we are going to discuss in this section is the notion of computer types. 

Super Computers - In the computer world, the largest computers, not necessarily in size, are “supercomputers”.  These are at the top of the food chain in terms of price and abilities.  Perhaps the best known supercomputers are built by Cray (www.cray.com).  Cray also provides a nice overview of their notion of a supercomputer: http://www.cray.com/supercomputing/

Main Frames – You may here this term.  Main frames are essentially large computers (very large in size) that were used by large groups (i.e. corporations, universities, etc.).  The size was sort of proportional to the abilities.  Today we do not use main frames, but instead you will hear the term servers or more specifically, enterprise servers.

Servers – Servers are computers that are configured (with hardware and software) to “serve” many other individuals.  For instance, here at Juniata College, we have a mail server that processes all of your email.

Desktops – This is a class of computer that includes PC’s and UNIX machines like those made by SUN.  Sometimes we talk about workstations (SUN usually refers to their products as workstations).  Workstations are basically desktops with a more powerful processor and other abilities.

PC – PC or personal computer is the generic term for a computer used by a single person, although we often network PC’s.  If you brought a PC to campus, you more than likely have plugged it into the network here on campus.  Most people refer to PC’s as those computers using Windows and use the term “mac” for a Macintosh computer on the desktop.  It’s just terminology.

Laptop – Laptops are small PC’s that have integrated keyboards, monitors, and some type of pointing device.

Palms and Handhelds – These are fairly new to the computing scene.  They are small computers that typically do not have a hard drive.  They also incorporate touch screen technology for most of the input, although you can add a keyboard for input.  These are also referred to as PDA’s or personal digital assistants. 

Tablets – Tablets are very new to the market place.  These are sort of mid-way between a laptop and PDA.  They incorporate touch screen technology, but also have an integrated keyboard.

Embedded Computers - Today, computers are found in everything from cars to cell phones to toasters to credit cards. How many computers have you used today and didn't even realize it?

Wearables -?!?!?!

One of the most interesting projects or efforts that includes HCI and input devices is the MIThril project.  This is a “wearable” computer platform.  That’s right – you wear it and there are multiple input (and output) devices.  Check it out!

http://www.media.mit.edu/wearables/mithril/index.html

 

 

Moodle Discussion Assignment: Read about the MIThrill project and give us some feedback.  What are your thoughts?  What are the challenges of this project (hardware, software, input, output)?  Perhaps more importantly, where is this headed?  Where do you think computing platforms will be in the future?  Go to Moodle and navigate to the discussions and then the appropriate discussion activity. 

 

You should now check for additional readings/ assignments specific to your section.

 

Overview of Computer Software

• user interface
• hardware control
• memory management
• processing tasks management
• file management
• networking
• access control to system resources